Mobile communication terminal, IC card, mobile communication system, program, and communication charge notification method

ABSTRACT

The present invention provides a mobile communication terminal, an IC card, a mobile communication system, a program, and a communication charge notification method capable of easily indicating roaming communication charges and preventing a user from being unexpectedly charged for communication. A mobile phone  10  detects that it is located in a country B as a roaming area based on information transmitted from a base station  32 , inquires of a charge information related server  24  whether or not a communication charge information stored in a storage section  16  is the latest communication charge information, when the communication charge information is not the latest communication charge information, updates the stored communication charge information based on the communication charge information transmitted from the charge information related server  24 , reads the communication charge information of the country B from the storage section  16 , and displays the communication charge information on a display section  14.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a roaming mobile communicationterminal, an IC card provided in the mobile communication terminal, amobile communication system, a program executed by the mobilecommunication terminal, and a communication charge notification methodof notifying a user of communication charge information for roamingcommunication of the mobile communication terminal.

2. Description of Related Art

A mobile communication system includes a home location register (HLR)which manages movement and calling of a mobile communication terminalsuch as a mobile phone. Information for specifying each mobilecommunication terminal which receives a communication service in themobile communication network (home network), location informationindicating the location of each mobile communication terminal,subscriber information indicating the basic communication service (e.g.normal telephone call service) provided to each mobile communicationterminal, and the like are registered in the HLR. Location registration(attachment) occurs when a mobile communication terminal is turned on ora mobile communication terminal is located in the service area of a homenetwork or a roaming network. The HLR may update location informationduring attachment. The location information includes a countryidentification code, a communication network code, and a location codeindicating the location of the mobile communication terminal. When thelocation information differs from the location information at the latestattachment, or whenever the location information is changed due tomovement of the mobile communication terminal beyond the service area ofthe network, the HLR receives a request (location registration request)from the mobile communication terminal through a base station, and therequest is registered (location registration). A mobile communicationsystem controls call connection based on the subscriber informationregistered in the HLR when the mobile communication terminal has made acall or the mobile communication terminal has received a call.

A roaming service such as an international roaming service which allowsa mobile communication terminal used in Japan to be used in foreigncountries has been realized by a mobile communication system. The term“roaming” means that the communication provider which manages a homenetwork makes an agreement with a communication provider which managesanother mobile communication network to provide the home network userwith a similar service on another mobile communication network, or meansthis service.

When the mobile communication terminal issues a location registrationrequest in an area in which the mobile communication terminal can roam(roaming area), the location registration request is transferred to themobile communication system of the home network through a switchboard towhich the mobile communication terminal is connected, whereby thelocation information stored in the HLR is updated and the location isregistered. The HLR transmits the subscriber information to theswitchboard to which the mobile communication terminal is connected, andthe switchboard controls call connection based on the subscriberinformation. When the mobile communication terminal makes a call orreceives a call in the roaming area, the HLR transmits the subscriberinformation to the switchboard to which the mobile communicationterminal is connected, and the switchboard controls call connectionbased on the subscriber information.

Various inventions have been made to improve roaming service andincrease processing efficiency.

For example, a communication system has been disclosed which provides anappropriate service when distributing content using a roaming servicetaking the destination country and region into consideration (seeJP-A-2004-236182).

A mobile communication service control method and a mobile communicationservice control system capable of easily providing a service to aroaming user in a roaming area have also been disclosed (seeJP-A-2003-61132).

SUMMARY OF THE INVENTION

However, the communication charges for the international roaming service(see FIG. 7) are significantly higher than the domestic communicationcharges. Moreover, the amount of charges varies depending on the countrythe user is visiting. There may be a case where the user is charged whenreceiving a call using the international roaming service depending onthe country (e.g. the United States of America).

Therefore, the user may unexpectedly incur high communication charges.On the other hand, in order to know the communication charges beforemaking a call, the user must access the communication provider throughthe Internet or the like, designate the origin country and thedestination country, and search for the communication chargescorresponding to the communication environment. This process istroublesome and imposes a burden on the user.

An object of the present invention is to provide a mobile communicationterminal, an IC card, a mobile communication system, a program, and acommunication charge notification method capable of easily indicatingroaming communication charges and preventing a user from beingunexpectedly charged for communication.

The present invention achieves the above object by the following means.The following means is provided with symbols corresponding to theembodiments of the present invention so that the present invention isreadily understood. Note that the present invention is not limitedthereto.

A first aspect of the present invention provides a mobile communicationterminal (10) comprising: roaming area detection means (11, S110, 18,S310) for detecting whether or not the mobile communication terminal islocated in a roaming area; communication charge information acquisitionmeans (11) for acquiring communication charge information of the roamingarea in which the mobile communication terminal is located when theroaming area detection means has detected that the mobile communicationterminal is located in the roaming area; and communication chargeinformation notification means (11, 14, S160, 11, 14, S370) fornotifying a user of the communication charge information acquired by thecommunication charge information acquisition means.

In the mobile communication terminal (10) according to the first aspectof the present invention, the communication charge informationnotification means may notify the user of the charge information at anappropriate timing.

The mobile communication terminal (10) according to the first aspect ofthe present invention may comprise: base station transmissioninformation reception means (13, S100, 13, S300) for receivinginformation transmitted from a base station (22, 32); wherein theroaming area detection means may detect that the mobile communicationterminal is located in the roaming area based on the informationreceived by the base station transmission information reception means;and wherein the communication charge information notification means mayinclude display means (14) for displaying the communication chargeinformation acquired by the communication charge information acquisitionmeans.

In the mobile communication terminal (10) according to the first aspectof the present invention, the communication charge informationacquisition means may include communication charge information requestmeans for requesting a mobile communication system to provide thecommunication charge information of the roaming area in which the mobilecommunication terminal is located, and communication charge informationreception means for receiving the communication charge informationtransmitted from the mobile communication system in response to therequest from the communication charge information request means.

The mobile communication terminal (10) according to the first aspect ofthe present invention may comprise: communication charge informationstorage means (16) for storing the communication charge information ofeach roaming area; wherein the communication charge informationacquisition means may include communication charge information readmeans (11) for reading the communication charge information of theroaming area in which the mobile communication terminal is located fromthe communication charge information storage means based on theinformation received by the base station transmission informationreception means.

The mobile communication terminal (10) according to the first aspect ofthe present invention may comprise: update necessity inquiry means (11,13, S120) for inquiring of a mobile communication system (2) whether ornot it is necessary to update the communication charge informationstored in the communication charge information storage means; updatedinformation reception means (11, 13, S150) for receiving updatedinformation transmitted from the mobile communication system when themobile communication system has determined that it is necessary toupdate the communication charge information in response to the inquiryfrom the update necessity inquiry means; and update means (11) forupdating the communication charge information stored in thecommunication charge information storage means based on the updatedinformation received by the updated information reception means.

The mobile communication terminal (10) according to the first aspect ofthe present invention may comprise: roaming area notification means fornotifying the user that the roaming area detection means has detectedthat the mobile communication terminal is located in the roaming area;wherein the communication charge information notification means maynotify the user of the communication charge information acquired by thecommunication charge information acquisition means when directed by theuser.

In the mobile communication terminal (10) according to the first aspectof the present invention, when the user has issued a call instruction ora call preparation instruction in the roaming area in which the mobilecommunication terminal is located, the communication charge informationnotification means may notify the user of the communication chargeinformation for communication with the destination.

In the mobile communication terminal (10) according to the first aspectof the present invention, when receiving a call in the roaming area inwhich the mobile communication terminal is located, the communicationcharge information notification means may notify the user of thecommunication charge information for communication after receiving thecall when the receiving call has been processed before the communicationis established.

In the mobile communication terminal (10) according to the first aspectof the present invention, when the roaming area detection means hasdetected that the mobile communication terminal is located in two ormore roaming areas, the communication charge information acquisitionmeans may acquire the communication charge information of each of theroaming areas in which the mobile communication terminal is located; andthe communication charge information notification means may notify theuser of the communication charge information of each of the roamingareas acquired by the communication charge information acquisitionmeans.

A second aspect of the present invention provides an IC card (18)removable from a mobile communication terminal and capable ofcommunicating with the mobile communication terminal in which the ICcard is installed, the IC card comprising: roaming area detection meansfor detecting whether or not the mobile communication terminal islocated in a roaming area based on information received by the mobilecommunication terminal, in which the IC card is installed, from a basestation; and communication charge information display request means forrequesting the mobile communication terminal to display communicationcharge information of the roaming area in which the mobile communicationterminal is located when the roaming area detection means has detectedthat the mobile communication terminal is located in the roaming area.

The IC card according to the second aspect of the present invention maycomprise: communication charge information acquisition means foracquiring the communication charge information of the roaming area froma mobile communication system through the mobile communication terminalin which the IC card is installed; wherein, when the roaming areadetection means has detected that the mobile communication terminal islocated in the roaming area, the communication charge informationdisplay request means may transmit the communication charge informationacquired by the communication charge information acquisition means tothe mobile communication terminal and request the mobile communicationterminal to display the communication charge information.

A third aspect of the present invention provides a mobile communicationsystem (2-2) for allowing roaming communication of a mobilecommunication terminal, the mobile communication system comprising:roaming area detection means (24-2, S210) for detecting whether or notthe mobile communication terminal is located in a roaming area based ona location registration request received from the mobile communicationterminal; communication charge information storage means (25) forstoring communication charge information indicating communicationcharges for the roaming communication; communication charge informationread means (25) for reading the communication charge information of theroaming area in which the mobile communication terminal is located fromthe communication charge information storage means; and communicationcharge information transmission means (25, 24-2) for transmitting thecommunication charge information read by the communication chargeinformation read means to the mobile communication terminal.

A fourth aspect of the present invention provides a program forexecution by a mobile communication terminal, the program comprising: aroaming area detection procedure (S110, S310) of detecting whether ornot the mobile communication terminal is located in a roaming area; acommunication charge information acquisition procedure of acquiringcommunication charge information of the roaming area in which the mobilecommunication terminal is located when the roaming area detectionprocedure has detected that the mobile communication terminal is locatedin the roaming area; and a communication charge information notificationprocedure (SI 60, S370) of notifying a user of the communication chargeinformation acquired by the communication charge information acquisitionprocedure.

The program according to the fourth aspect of the present invention maycomprise: a base station transmission information reception procedure(S100, S300) of receiving information transmitted from a base station;wherein the roaming area detection procedure may detect that the mobilecommunication terminal is located in the roaming area based on theinformation received by the base station transmission informationreception procedure; and wherein the communication charge informationnotification procedure may include a display procedure (S160, S370) ofdisplaying the communication charge information acquired by thecommunication charge information acquisition procedure.

In the program according to the fourth aspect of the present invention,the communication charge information acquisition procedure may include acommunication charge information request procedure of requesting amobile communication system to provide the communication chargeinformation of the roaming area in which the mobile communicationterminal is located, and a communication charge information receptionprocedure of receiving the communication charge information transmittedfrom the mobile communication system in response to the request from thecommunication charge information request procedure.

In the program according to the fourth aspect of the present invention,the communication charge information acquisition procedure may include acommunication charge information read procedure of reading thecommunication charge information of the roaming area in which the mobilecommunication terminal is located from the stored communication chargeinformation based on the information received by the base stationtransmission information reception procedure.

The program according to the fourth aspect of the present invention maycomprise: an update necessity inquiry procedure (S120, S320) ofinquiring of a mobile communication system whether or not it isnecessary to update stored communication charge information; an updatedinformation reception procedure (S150, S350) of receiving updatedinformation transmitted from the mobile communication system when themobile communication system has determined that it is necessary toupdate the communication charge information in response to the inquiryfrom the update necessity inquiry procedure; and an update procedure ofupdating the stored communication charge information based on theupdated information received by the updated information receptionprocedure.

The program according to the fourth aspect of the present invention maycomprise: a roaming area notification procedure of notifying the userthat the roaming area detection procedure has detected that the mobilecommunication terminal is located in the roaming area; wherein thecommunication charge information notification procedure may notify theuser of the communication charge information acquired by thecommunication charge information acquisition procedure when directed bythe user.

In the program according to the fourth aspect of the present invention,when the user has issued a call instruction or a call preparationinstruction in the roaming area in which the mobile communicationterminal is located, the communication charge information notificationprocedure may notify the user of the communication charge informationfor communication with the destination.

In the program according to the fourth aspect of the present invention,when receiving a call in the roaming area in which the mobilecommunication terminal is located, the communication charge informationnotification procedure may notify the user of the communication chargeinformation for communication after receiving the call when thereceiving call has been processed before the communication isestablished.

In the program according to the fourth aspect of the present invention,when the roaming area detection procedure has detected that the mobilecommunication terminal is located in two or more roaming areas, thecommunication charge information acquisition procedure may acquire thecommunication charge information of each of the roaming areas in whichthe mobile communication terminal is located; and the communicationcharge information notification procedure may notify the user of thecommunication charge information of each of the roaming areas acquiredby the communication charge information acquisition procedure.

A fifth aspect of the present invention provides a communication chargenotification method for execution by a mobile communication system (1)for notifying a user of communication charge information for roamingcommunication of a mobile communication terminal (10), the methodcomprising: an area detection step (S110, S210, S310) of detectingwhether or not the mobile communication terminal is located in a roamingarea based on information received by the mobile communication terminalfrom a base station (22, 32); a communication charge informationacquisition step of acquiring communication charge information of theroaming area in which the mobile communication terminal is located whenthe area detection step has detected that the mobile communicationterminal is located in the roaming area; and a communication chargeinformation notification step (S160, S250, S370) of notifying the userof the communication charge information acquired by the communicationcharge information acquisition step.

According to the mobile communication terminal, the IC card, the mobilecommunication system, the program, and the communication chargenotification method of the present invention, the following effects canbe obtained.

(1) When the mobile communication terminal has detected that the mobilecommunication terminal is located in the roaming area, the mobilecommunication terminal displays the communication charge information ofthe roaming area to notify the user of the communication charges.Therefore, the user can be simply notified of the communication chargesbefore performing roaming communication, whereby convenience to the usercan be improved, and the user can be prevented from being unexpectedlycharged for the use of roaming.

(2) In particular, convenience to the user can be further improved bynotifying the user of the communication charges at an appropriate timingset in advance.

(3) Since the mobile communication terminal detects that the mobilecommunication terminal is located in the roaming area based on theinformation (e.g. location registration area information) transmittedfrom the base station, the location of the mobile communication terminalcan be efficiently detected by utilizing known processing performedbetween the mobile communication terminal and the mobile communicationsystem. Moreover, the present invention can be realized withoutmodifying a known mobile communication system to a large extent.

(4) Since the mobile communication terminal acquires the communicationcharge information by reading the stored communication chargeinformation, an increase of the amount of data transferred can bereduced in comparison with the case of acquiring the communicationcharge information from the mobile communication system, whereby theprocessing speed can be increased, and the present invention can bereadily realized.

(5) Since the mobile communication terminal updates the communicationcharge information based on the updated information received from themobile communication system, the user can be notified of correctcommunication charge information.

(6) Since the mobile communication terminal notifies the user that themobile communication terminal is located in the roaming area andnotifies the user of the communication charges according to theinstruction, the user can easily know a change in the communicationcharges and can easily know the communication charges if necessary.

(7) Since the mobile communication terminal notifies the user of thecommunication charge information for communication with the destinationwhen the user has issued a call instruction or a call preparationinstruction in the roaming area, the user can be appropriately notifiedof the communication charge information, because the user can determinewhether or not to proceed with the call based on the communicationcharge information displayed in relation to the call operation.

(8) Since the mobile communication terminal notifies the user of thecommunication charge information when processing for receiving a callhas been performed before the communication is established whenreceiving a call in the roaming area, the user can be appropriatelynotified of the communication charge information, because the user canknow the communication charges immediately before answering the call anddetermine whether or not to answer the call.

(9) Since the mobile communication system stores the communicationcharge information and provides the communication charge information tothe mobile communication terminal, the user can be notified of correctcommunication charge information.

(10) Since the user is notified of the communication charge informationof each roaming area when it has been detected that the mobilecommunication terminal is located in two or more roaming areas, the usercan select the communication network through which the user communicatesbased on the communication charge information.

(11) Since the IC card includes the roaming area detection means and thecommunication charge information display request means, the presentinvention can be realized without modifying a known mobile communicationterminal to a large extent. Likewise, even if the user replaces themobile communication terminal with another mobile communicationterminal, the present invention can be easily realized by providing theIC card to the new mobile communication terminal.

Other objects, features, and advantages of the invention willhereinafter become more readily apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a schematic configuration of a mobilecommunication system according to one embodiment of the presentinvention (first embodiment).

FIG. 2 is a block diagram showing a configuration of a mobilecommunication terminal and a mobile communication system according tothe present invention (first embodiment).

FIG. 3 is a flowchart showing the operation, program, and communicationcharge notification method of a mobile communication terminal and amobile communication system according to the present invention (firstembodiment).

FIG. 4 is a block diagram showing a configuration of a mobilecommunication terminal and a mobile communication system according tothe present invention (second embodiment).

FIG. 5 is a flowchart showing the operation, program, and communicationcharge notification method of a mobile communication terminal and amobile communication system according to the present invention (secondembodiment).

FIG. 6 is a flowchart showing the operation, program, and communicationcharge notification method of a mobile communication terminal and amobile communication system according to the present invention(modification).

FIG. 7 is a communication charge table indicating communication chargesfor international roaming.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENT

The present invention achieves the object of easily indicating roamingcommunication charges and preventing a user from being unexpectedlycharged for communication by a mobile communication terminal comprisinga base station transmission information reception section which receivesinformation being transmitted from a base station, an area locationdetection section which detects whether or not the mobile communicationterminal is located in a roaming area based on the information receivedby the base station transmission information reception section, acommunication charge information acquisition section which acquirescommunication charge information of the roaming area when the arealocation detection section has detected that the mobile communicationterminal is located in the roaming area, and a communication chargeinformation notification section which notifies a user of thecommunication charge information acquired by the communication chargeinformation acquisition section.

First Embodiment

The present invention is described below in detail by way of embodimentswith reference to the drawings.

FIG. 1 is a view showing a schematic configuration of a mobilecommunication system according to a first embodiment of the presentinvention.

As shown in FIG. 1, a communication system 1 includes a mobile phone 10,a mobile communication system 2 which mediates communication between themobile phone 10 and another communication terminal, and the like. Thecommunication system 1 allows the mobile phone 10 carried out from acountry A (home area of the mobile phone 10) to a country B (roamingarea) during traveling or the like to communicate (voice communicationor data communication) with another communication terminal by roaming.

In general, the home area in which the communication service using ahome network is provided and the roaming area in which the communicationservice using a roaming network is provided differ regionally.Specifically, the home area and the roaming area differ depending on thecountry, such as the case where the home area and the roaming area existin a single country or the case where two or more roaming areas exist ina single country. The following description is given on the assumptionthat the home area exist in the country A and the roaming area exist inthe country B for convenience.

FIG. 2 is a block diagram showing a configuration of a mobilecommunication terminal and a mobile communication system according tothe first embodiment of the present invention.

As shown in FIG. 2, the mobile phone 10 is a mobile communicationterminal which can perform mobile communication, and is realized byproviding a specific program in a mobile phone including a CPU, astorage device, an input/output device, a wireless communication device,and the like. The mobile phone 10 includes a control section 11, aninput section 12, a communication section 13, a display section 14, avoice input/output section 15, a storage section 16, and a reader/writer(R/W) 17 connected with the control section 11, a user identity module(UIM) 18 connected with the R/W 17, and the like.

The control section 11 includes a CPU and the like, and is realized bycausing the CPU to execute a program stored in a storage device. Thecontrol section 11 centrally controls the mobile phone 10. The detailsof the function of the control section 11 are described later withreference to FIG. 3.

The input section 12 is an input device for inputting informationaccording to the user's operation, such as input buttons for allowingthe user to deliver information to the mobile phone 10. Thecommunication section 13 includes an antenna and the like, and controlswireless communication with base stations 22 and 32. The display section14 is a display device (e.g. display) for allowing the mobile phone 10to deliver information to the user. The voice input/output section 15 isa voice input/output device, and includes a voice input section (e.g.microphone) for inputting voice and a sound output section (e.g.speaker) which outputs voice.

The storage section 16 is a storage device (e.g. memory or hard disk)which stores a program and data. The storage section 16 stores chargerelated information relating to a communication charge such as a chargeinformation table and its version information. As shown in FIG. 7, thecharge information table indicates roaming communication charges perunit time and the like, in which the country code, time difference,communication provider, outgoing call communication charges per unittime, incoming call communication charges per unit time, and the likeare associated with each roaming area such as a destination (roaming)country. FIG. 7 shows the charge information table when the country A isJapan. For example, the outgoing call communication charges differdepending on the attribute of the destination area, such ascommunication from the roaming area in which the mobile phone 10 islocated (country B in this embodiment) to the same roaming area (countryB), communication from the roaming area (country B) to the user's homearea (Japan), or communication from the roaming area (country B) to anarea other than the above areas (Japan and country B).

The R/W 17 is a communication interface with the UIM 18, and writes datainto or reads data from the UIM 18 under control of the control section11.

The UIM 18 is an IC card which records user identification information.The UIM 18 is installed in the mobile phone 10 and used for useridentification and the like. The UIM 18 includes a central processingunit (CPU), a storage device such as a RAM, ROM, or EEPROM, acommunication interface (e.g. contact terminal) which interfacescommunication with the R/W 17, and the like (not shown). The UIM 18 is aportable information processing device which can communicate with themobile phone 10 through the R/W 17, receives a command (instruction)from the mobile phone 20, performs processing according to the command,and transmits the processing result to the mobile phone 20 as aresponse.

The UIM 18 also records user's personal information such as a telephonebook and credit payment personal identification information. The UIM maybe called a universal subscriber identity module (USIM) or a subscriberidentity module (SIM). Note that an SD card having a similar functionand including a chip module may be installed in the mobile phone 10instead of the UIM 18. The type of IC card installed in the mobile phone10 is not limited.

The UIM 18 stores location information. The location information isinformation which includes a country code which identifies the countryin which the mobile phone 10 is located, a communication network codefor identifying the communication network in which the mobile phone 10is located, a location code which indicates the visited location and isused to identify the wireless zone (location registration area) of thecommunication system 20, and the like, and indicates the location of themobile phone 10 and an available communication network. Each of the basestations 22 and 32 provided corresponding to the wireless zone of themobile communication system 1 continuously and repeatedly transmitslocation registration area information including a location code foridentifying the wireless zone. The base station 22 of a home network 20continuously and repeatedly transmits the location registration areainformation including a country identification code indicating thecountry A and a communication network identification code indicating thehome network 20, and the base station 32 of a roaming network 30transmits the location registration area information including thecountry identification code indicating the country B and thecommunication network identification code indicating the roaming network30. The mobile phone 10 receives the location registration areainformation repeatedly transmitted from the nearest base station, and,when the location information included in the location registration areainformation has been changed, writes the location information in the UIM18 to update the location information (see FIG. 3 described later).

The mobile communication system 2 includes the home network 20 which isa mobile communication system provided in the country A, the roamingnetwork 30 which is a mobile communication system provided in thecountry B, and the like (see FIG. 1). The home network 20 and theroaming network 30 are connected through a communication line and apoint of interface (POI). The mobile communication system 2 controlsconnection of roaming communication by the mobile phone 10. The homenetwork 20 is a mobile communication system which provides a mobilecommunication service such as a mobile phone call service to the mobilephone 10 in the country A, and is managed by a communication provider(communication provider A) with which the user of the mobile phone 10has a communication service agreement. The roaming network 30 is asystem which is managed by a communication provider B with which thecommunication provider A has a roaming agreement and provides a mobilecommunication service in the country B.

The home network 20 includes a switchboard 21, the base station 22, anHLR 23, and a charge information related server 24 connected with theswitchboard 21, and the like. The base station 22 is distributed in thecountry A corresponding to the wireless zone, and performs wirelesscommunication with the mobile phone 10 in the corresponding wirelesszone, such as transmitting the location registration area information inthe corresponding wireless zone (location registration area).

The switchboard 21 controls call connection from or to the mobile phone10 in the communication area of the home network 20. The HLR 23 is ahome location register which performs movement management and callmanagement for the mobile phone 10, in which subscriber information isregistered. The mobile phone 10 performs wireless communication with thebase station 22 in the country A, and communicates with anothercommunication terminal through the switchboard 21 connected with thebase station 22.

The charge information related server 24 is realized by providing aspecific program and data in a server computer including a CPU, astorage device, an input/output device, a communication device, and thelike. The charge information related server 24 stores charge relatedinformation such as a charge information table and its versioninformation. As shown in FIG. 7, the charge information table indicatesroaming communication charges per unit time and the like, in which thecountry code, time difference, communication provider, outgoing callcommunication charges per unit time, incoming call communication chargesper unit time, and the like are associated with each destination(roaming) country.

The charge information related server 24 determines whether or not thecharge information table stored in the mobile phone 10 is the latestcharge information table in response to inquiry the from the mobilephone 10. When the charge information table is not the latest chargeinformation table, the charge information related server 24 provides thelatest charge information table to the mobile phone 10 (see FIG. 3described later).

The roaming network 30 includes the base station 32 distributed in thecountry B corresponding to the wireless zone, a switchboard 31 which isconnected with the base station 32 and controls call connection when themobile phone 10 in the communication area of the roaming network 30makes an outgoing call or receives a call. The mobile phone 10 performswireless communication with the base station 32 in the roaming network30, and communicates with another communication terminal through theswitchboard 31 connected with the base station 32.

FIG. 3 is a flowchart showing the operation, program, and communicationcharge notification method of the mobile communication terminal and themobile communication system according to the present invention. FIG. 3shows the process of notifying the user of the communication charge whenthe mobile phone 10 makes an outgoing call. The following descriptionfocuses on the processing of the control section 11 of the mobile phone10, the HLR 23 of the mobile communications network system 2, and thecharge information related server 24.

The user turns on the mobile phone 10 for the first time after enteringthe country B. In a step 100 (“step” is hereinafter abbreviated as “S”),the mobile phone 10 selects a network, and attachment occurs between themobile phone 10 and the mobile communication system 2, as shown in FIG.3. Then, the mobile phone 10 receives the location registration areainformation from the nearest base station 32 of the roaming network 30,and determines whether or not the location information included in thelocation registration area information differs from the locationinformation which has been received from the base station 22 and storedin the UIM 18 before leaving the country A. After confirming thedifference in the location information, the mobile phone 10 updates thelocation information stored in the UIM 18 and transmits a locationregistration request to the base station 32. In the mobile communicationsystem 2, the switchboard 31 receives the location registration requestthrough the base station 32, transfers the location registration requestto the HLR 23, and updates the location information of the mobile phone10 to the location information including the country code of the countryB, the communication network code of the roaming network 30, and thelocation code of the wireless zone in which the mobile phone 10 islocated.

The mobile phone 10 detects that the mobile phone 10 is located in theroaming area based on the location information received from the basestation 32, and identifies that the roaming area in which the mobilephone 10 is located is the country B (S110). The mobile phone 10transmits the version information such as the version number of thecharge information table stored in the storage section 16 to theswitchboard 31, and the switchboard 31 transfers the version informationto the charge information related server 24 (S120).

The charge information related server 24 determines whether or not thecharge information table stored in the mobile phone 10 is the latestcharge information table based on the version information (S130). Whenthe charge information related server 24 has determined that the chargeinformation table is the latest charge information table, the chargeinformation related server 24 transmits to the mobile phone 10 anotification indicating that the charge information table need not beupdated (S140). The mobile phone 10 receives the notification, reads thecommunication charge information of the country B from the chargeinformation table stored in the storage section 16 based on the locationinformation received from the base station 32, displays thecommunication charge information on the display section 14 (S160) tonotify the user of the communication charge information.

When the charge information related server 24 has determined that thecharge information table is not the latest charge information table, thecharge information related server 24 transmits the latest chargeinformation table to the mobile phone 10 (S150). The mobile phone 10receives the latest charge information table and writes the latestcharge information table into the storage section 16 to update thecharge information table. The mobile phone 10 then reads thecommunication charge information of the country B from the chargeinformation table stored in the storage section 16 and displays thecommunication charge information on the display section 14 (S160).

As described above, according to the first embodiment, when the mobilephone 10 is turned on and detects that the mobile phone 10 is located inthe country B, the mobile phone 10 displays the communication chargeinformation of the country B on the display section 14 to notify theuser of the communication charges. Therefore, the user can be simplynotified of the communication charges before performing roamingcommunication, whereby convenience to the user can be improved, and theuser can be prevented from being unexpectedly charged for the use ofroaming.

Since the mobile phone 10 detects that it is located in the country Bbased on the location registration area information transmitted from themobile communication system 2 to each area, the location of the mobilephone 10 can be efficiently detected by utilizing known processingperformed between the mobile communication terminal and the mobilecommunication system. Moreover, the present invention can be realizedwithout modifying a known mobile communication system to a large extent.

In addition, since the mobile phone 10 acquires the latest communicationcharge information from the mobile communication system 2, the user canbe notified of correct communication charge information.

Second Embodiment

FIG. 4 is a block diagram showing a configuration of a mobilecommunication terminal and a mobile communication system according to asecond embodiment of the present invention.

Note that sections having the same functions as in the first embodimentare indicated by the same symbols or symbols to which an identicalsymbol is attached on the end. Description of these sections isappropriately omitted.

As shown in FIG. 4, a communication system 1-2 includes a mobile phone10-2 and a mobile communication system 2-2, and allows the mobile phone10-2 carried out from the country A to the country B to communicate withanother communication terminal through the mobile communication system2-2.

The mobile phone 10-2 includes a control section 11-2, the input section12, the communication section 13, the display section 14, the voiceinput/output section 15, a storage section 16-2, and the R/W 17connected with the control section 11-2, the UIM 18 connected with theR/W 17, and the like.

The control section 11-2 includes a CPU and the like, and is realized bycausing the CPU to execute a program stored in a storage device. Thecontrol section centrally controls the mobile phone 10. The details ofthe function of the control section 11 are described later withreference to FIG. 5. The storage section 16-2 need not store the chargerelated information such as the charge information table, differing fromthe first embodiment.

The mobile communication system 2-2 includes a home network 20-2 and aroaming network 30 connected through a communication line and a POI, forexample.

The home network 20-2 includes the switchboard 21, the base station 22,an HLR 23-2, and a charge information related server 24-2 connected withthe switchboard 21, a charge related information database 25 (“database”is hereinafter abbreviated as “DB”) connected with the chargeinformation related server 24-2, and the like.

When the HLR 23-2 has updated the location information of the mobilephone 10-2 in response to the location registration request from themobile phone 10-2, the HLR 23-2 notifies the charge information relatedserver 24-2 to that effect.

When the charge information related server 24-2 receives the locationinformation change notification from the HLR 23-2, the chargeinformation related server 24-2 detects that the mobile phone 10 islocated in the roaming area of the country B based on the updatedregistration position of the mobile phone 10, acquires the chargeinformation corresponding to the country B from the charge relatedinformation DB 25, and provides the charge information to the mobilephone 10 (see FIG. 5 described later).

FIG. 5 is a flowchart showing the operation, program, and communicationcharge notification method of the mobile communication terminal and themobile communication system according to the present invention. FIG. 5shows the process of notifying the user of the communication charge whenthe mobile phone 10-2 makes an outgoing call. The following descriptionfocuses on the processing of the control section 11-2 of the mobilephone 10-2, the HLR 23-2 of the mobile communications network system2-2, and the charge information related server 24-2.

As shown in FIG. 5, the user turns on the mobile phone 10-2 for thefirst time after entering the country B, and attachment occurs betweenthe mobile phone 10-2 and the mobile communication system 2-2 (S200).After confirming the difference in the location code, the mobile phone10-2 updates the location information stored in the UIM 18 and transmitsa location registration request to the base station 32. The HLR 23-2updates the location information of the mobile phone 10-2 to thelocation information indicating the wireless zone in which the mobilephone 10-2 is located in the country B in response to the locationregistration request, and notifies the charge information related server24-2 to that effect. The charge information related server 24-2 receivesthe location information change notification from the HLR 23-2, anddetects that the mobile phone 10-2 is located in the roaming area of thecountry B based on the location information change notification (S210).The charge information related server 24 requests the charge relatedinformation DB 25 to transmit the charge information corresponding tothe roaming area (country B) (S220), and receives the charge information(S230).

The charge information related server 24 transmits the chargeinformation received from the charge related information DB 25 to themobile phone 10-2 through the switchboard 31 using a short messageservice (SMS) (S240). The mobile phone 10-2 receives the SMS anddisplays the charge information on the display section 14 (S250).

As described above, according to the second embodiment, the same effectas in the first embodiment 1 can be obtained even when the mobilecommunication system 2-2 detects the roaming area of the mobile phone10-2, stores the communication charge information, and provides thecommunication charge information to the mobile phone 10-2.

Modification

The present invention is not limited to the above-described embodiments,and various modifications and variations may be made. Such modificationsand variations are also within the scope of equivalence of the presentinvention. In the above-described embodiment, the communication system 1or 1-2 displays the communication charges to the mobile phone 10 or 10-2when the mobile phone 10 or 10-2 has been turned on after entry into thecountry B and attached to the mobile communication system. Note that theevent which prompts the communication system to notify the user of thecommunication charges is not limited thereto. When the country A and thecountry B are connected by land and the mobile phone 10 or 10-2 is movedfrom the communication area of the home network 20 or 20-2 to thecommunication area of the roaming network 30 in a state in which themobile phone 10 or 10-2 is turned on, the communication charges may bedisplayed on the display section 14 when it has been detected that themobile phone 10 or 10-2 is located in the roaming area, and the user maybe notified by an alarm such as voice or a vibration. When it has beendetected that the mobile phone 10 or 10-2 is located in the roamingarea, the mobile phone 10 or 10-2 may notify the user that the mobilephone 10 or 10-2 is located in the roaming area or that thecommunication charges differ from the communication charges in thecountry A, and may display the communication charge information whenrequested by the user.

When the user makes a call using the mobile phone 10 or 10-2 in theroaming area, the communication charges may be displayed on the displaysection 14 when the user has directed the mobile phone 10 or 10-2 tomake a call by operating the input section 12 or the user has directedthe mobile phone 10 or 10-2 to prepare to make a call, such as callingthe telephone book function of the mobile phone 10 or 10-2. In thiscase, the communication charge information may be updated or the mobilephone 10 or 10-2 and the charge information related server 24 or 24-2may communicate in order to acquire the communication charge informationwhen it has been detected that the mobile phone 10 or 10-2 is located inthe roaming area or when the user has directed the mobile phone 10 or10-2 to make a call. The timing at which the communication chargeinformation is updated or the mobile phone 10 or 10-2 and the chargeinformation related server 24 or 24-2 communicate is not limited insofaras the timing occurs in the period between the time at which it isdetected that the mobile phone 10 or 10-2 is located in the roaming areaand the time at which the communication charges are displayed. When theabove timing occurs when the user has directed the mobile phone 10 or10-2 to make a call, the mobile communication system 2 or 2-2 mayidentify the country in which the destination communication terminalexists based on the telephone number (fixed telephone), information fromthe HLR in which the subscriber information of the destinationcommunication terminal is stored, and the like, and may display thecommunication charges corresponding to the origin country (country B)and the destination country on the display section 14. This allows theuser to be appropriately notified of the communication chargeinformation, because the user can determine whether or not to proceedwith the call based on the communication charge information displayed inrelation to the call operation.

When the mobile phone 10 or 10-2 receives a call in the roaming area,the communication charge information for communication after receivingthe call may be displayed on the display section 14 when call receptionprocessing has been performed before the communication is established.Specifically, the communication charge information may be displayed onthe display section 14 when processing such as authentication, channelnotification reception, or calling has been performed before the mobilephone 10 or 10-2 returns a response notification to the caller toestablish communication. In this case, the timing at which the mobilephone 10 or 10-2 and the charge information related server 24 or 24-2communicate in order to update the communication charge information oracquire the communication charge information is not limited. The mobilecommunication system 2 or 2-2 may identify the country in which thecaller's communication terminal exists based on the caller's telephonenumber and the like, and may display the communication chargescorresponding to the origin country and the destination country (countryB) on the display section 14.

This allows the user to be appropriately notified of the communicationcharge information, because the user can know the communication chargesimmediately before answering the call and determine whether or not toanswer the call.

In the above-described embodiment, when the mobile phone 10 or 10-2 islocated in two or more roaming areas, the communication system 1 maydetect that the mobile phone 10 or 10-2 is located in two or moreroaming areas, and notify the user of the communication chargeinformation of each roaming area The statement “the mobile phone 10 or10-2 is located in two or more roaming areas” means that the roamingnetwork 30 managed by the communication provider B and a roaming network30′ (not shown) managed by a communication provider C which makes aroaming agreement with the communication provider A exist in the countryB, and the mobile phone 10 or 10-2 is located in the area in which theroaming area in which the roaming service is provided by the roamingnetwork 30 and the roaming area in which the roaming service is providedby the roaming network 30′ overlap.

The mobile phone 10 or 10-2 receives the location registration areainformation transmitted from the base station 32 of each of the roamingnetworks 30 and 30′, and detects that the mobile phone 10 or 10-2 islocated in the roaming networks 30 and 30′ based on the communicationnetwork code included in the location registration area information.When the mobile phone 10 or 10-2 is located in this area, thecommunication system 1 may notify the user of the communication chargeinformation of the roaming area of the roaming network 30 and thecommunication charge information of the roaming area of the roamingnetwork 30′. As the notification method, the communication system 1 mayseparately notify the user of the information of each communicationprovider such as the communication charge information of each of theroaming networks 30 and 30′ using an SMS or the like, or maycollectively notify the user of the communication charge information ofeach of the available roaming networks 30 and 30′ using an SMS or thelike when the communication system 1 has detected that the mobile phone10 or 10-2 is located in the roaming networks 30 and 30′. Thecommunication system 1 may also notify the user of the information ofcommunication providers in the country B such as the communicationcharges for all roaming networks available in the country B. Thecommunication system 1 may not notify the user of this information whenthe location of the mobile phone 10 or 10-2 is registered again in thecountry B through the roaming networks 30 and 30′ after thecommunication. When the communication system 1 separately notifies theuser of the communication charges, the communication system 1 may notnotify the user of the communication charges when the location of themobile phone 10 or 10-2 is registered again through the roaming networks30 and 30′.

In general, when the mobile phone 10 can use two or more communicationnetworks provided by two or more communication providers, the mobilephone 10 selects one of the communication networks based on whether ornot the home network is included, whether or not the communicationnetwork previously used is included, the field intensity of thecommunication network, the priority network list stored in the USIM 18,and the like.

The user can select the communication network by being collectivelynotified of the communication charges for the available roaming networks30 and 30′, whereby convenience to the user can be improved. The mobilephone 10 may be set to automatically use a less expensive roamingnetwork when acquiring the communication charges for the roamingnetworks 30 and 30′, and the user may be notified of the communicationcharges for the less expensive roaming network.

In the above-described embodiment, the mobile communication system 2 or2-2 registers the location information indicating the location in thecountry B in the HLR 23 or 23-2. When the roaming network 30 is providedwith a gateway location register (GLR), the mobile communication system2 or 2-2 may register the location information in the GLR. The amount ofdata transferred between the home network 20 or 20-2 and the roamingnetwork 30 is increased especially in urban areas when the location isregistered each time in the HLR 23 or 23-2 of the home network 20 or20-2 by the roaming service. In order to deal with this problem, thelocation concerning the movement of the mobile phone 10 or 10-2 into theroaming area is registered in the HLR 23 or 23-2 for the first time, andduplicate information is stored in the GLR of the roaming network 30.The location is registered in the GLR for the subsequent movement toreduce the amount of data transferred and to enable utilization of thesubscriber information without accessing the HLR 23 or 23-2.

In the above-described embodiment, the HLR 23 or 23-2, the chargeinformation related server 24 or 24-2, and the charge relatedinformation DB 25 are provided in the home network 20 or 20-2. Note thatthe HLR 23 or 23-2, the charge information related server 24 or 24-2,and the charge related information DB 25 may be provided in the roamingnetwork 30 insofar as the HLR 23 or 23-2, the charge information relatedserver 24 or 24-2, and the charge related information DB 25 cancommunicate with the mobile phone 10 through the switchboard 31 and thelike. The installation location and the network to which these elementsbelong are not limited.

In the above-described embodiment, the mobile phone 10 detects that themobile phone 10 is located in the roaming area based on the locationinformation received from the base station 32. Note that the detectionmethod is not limited thereto insofar as the mobile phone 10 can detectthat it is located in the roaming area based on information receivedfrom the base station 32. The mobile phone 10 may detect that it islocated in the roaming area based on another piece of informationreceived from the base station 32.

In the first embodiment, the UIM 18, the IC chip attached to the mobilephone 10, or the like may have the functions of the control section 11and the storage section 16 of the mobile phone 10 according to thepresent invention, such as detecting that the mobile phone 10 is locatedin the roaming area, inquiring of the charge information related server24 relating to the charge information table, and managing the chargeinformation table.

As shown in FIG. 6, the UIM 18 may request the mobile phone 10 toperform processing using a proactive command or the like to notify theuser of the communication charges under control of the UIM 18, forexample. The UIM 18 detects that the mobile phone 10 is located in theroaming area based on the location information (S310), and transmits theversion information of the stored charge information table to the chargeinformation related server 24 of the mobile communication system 2through the mobile phone 10 (S320). The charge information relatedserver 24 determines whether or not the charge information table is thelatest charge information table (S330). When the charge informationrelated server 24 has determined that the charge information table isthe latest charge information table, the charge information relatedserver 24 transmits to the UIM 18 of the mobile phone 10 a notificationindicating that the charge information table need not be updated (S340).When the charge information related server 24 has determined that thecharge information table is not the latest charge information table, thecharge information related server 24 transmits the latest chargeinformation table to the UIM 18 of the mobile phone 10 using a USIM/SIMapplication toolkit (SAT/USAT) or the like and overwrites the chargeinformation table stored in the UIM 18 with the latest chargeinformation table to update the charge information table (S350). The UIM18 transmits the communication charge information to the mobile phone 10and requests the mobile phone 10 to display the communication chargeinformation (S360), and the mobile phone 10 displays the communicationcharge information (S370).

The present invention can be realized without modifying a known mobilephone to a large extent by providing the UIM 18 having such functions.Likewise, even if the user replaces the mobile phone with another mobilephone, the present invention can be easily realized by providing the UIM18 to the new mobile phone.

In the first embodiment, when the mobile phone 10 has detected that themobile phone 10 is located in the roaming area, the mobile phone 10 mayrequest the charge information related server 24 to provide thecommunication charge information, receive the communication chargeinformation of the roaming area provided from the charge informationrelated server 24 in response to the request, and display thecommunication charge information on the display section 14.

In the first embodiment, when the mobile phone 10 has detected that itis located in the roaming area, the mobile phone 10 inquires of thecharge information related server 24 whether or not the chargeinformation table is the latest charge information table. The inquirytiming is not limited. The inquiry may be performed when making a call,receiving a call, or regularly (e.g. once a week).

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. A mobile communication terminal communicating with a mobilecommunication system, the mobile communication terminal comprising: basestation transmission information reception means for receivinginformation transmitted from a base station of the mobile communicationsystem; roaming area detection means for detecting whether or not themobile communication terminal is located in a roaming area based on theinformation received by the base station transmission informationreception means; communication charge information acquisition means foracquiring communication charge information of the roaming area in whichthe mobile communication terminal is located when the roaming areadetection means has detected that the mobile communication terminal islocated in the roaming area; communication charge information storagemeans for storing the communication charge information of the roamingarea acquired by the communication charge information acquisition means;update necessity inquiry means for inquiring of the mobile communicationsystem whether it is necessary to update the communication chargeinformation stored in the communication charge information storagemeans; updated information reception means for receiving updatedinformation transmitted from the mobile communication system when themobile communication system has determined that it is necessary toupdate the communication charge information in response to the inquiryfrom the update necessity inquiry means; update means for updating thecommunication charge information stored in the communication chargeinformation storage means based on the updated information received bythe updated information reception means; communication chargeinformation read means for reading the communication charge informationof the roaming area in which the mobile communication terminal islocated from the communication charge information storage means based oninformation received by the base station transmission informationreception means when the roaming area detection means has detected thatthe mobile communication terminal is located in the roaming area; andcommunication charge information notification means for notifying a userof the communication charge information acquired by the communicationcharge information read means; wherein the communication chargeinformation includes version information identifying whether thecommunication charge information is the latest information, and thecommunication charge information storage means having versioninformation storage means in a part of the communication chargeinformation storage means; the update necessity inquiry means havingversion information transmission means for transmitting the versioninformation stored in the version information storage means to a side ofthe mobile communication system, and further comprising:update-unnecessary information reception means for receiving informationthat the communication charge information is not a necessary updatetransmitted from the mobile communication system when the mobilecommunication system has determined that the communication chargeinformation stored in the communication charge information storage meansis the latest information in response to the version informationtransmitted by the version information transmission means.
 2. The mobilecommunication terminal according to claim 1, wherein the communicationcharge information notification means includes a display section tonotify the user of the charge information at an appropriate timing. 3.The mobile communication terminal according to claim 1, wherein thecommunication charge information acquisition means includescommunication charge information request means for requesting a mobilecommunication system to provide the communication charge information ofthe roaming area in which the mobile communication terminal is located,and communication charge information reception means for receiving thecommunication charge information transmitted from the mobilecommunication system in response to the request from the communicationcharge information request means.
 4. The mobile communication terminalaccording to claim 1, further comprising: roaming area notificationmeans for notifying the user that the roaming area detection means hasdetected that the mobile communication terminal is located in theroaming area; wherein the communication charge information notificationmeans notifies the user of the communication charge information whendirected by the user.
 5. The mobile communication terminal according toclaim 1, wherein, when the user has issued a call instruction to adestination the user wishes to reach or a call preparation instructionto a destination the user wishes to reach in the roaming area in whichthe mobile communication terminal is located, the communication chargeinformation notification means notifies the user of the communicationcharge information for communication with the destination the userwishes to reach.
 6. The mobile communication terminal according to claim1, wherein, when receiving a call in the roaming area in which themobile communication terminal is located, the communication chargeinformation notification means notifies the user of the communicationcharge information for communication after receiving the call when thereceiving call has been processed before the communication isestablished.
 7. The mobile communication terminal according to claim 1,wherein, when the roaming area detection means has detected that themobile communication terminal is located in two or more roaming areas,the communication charge information acquisition means acquires thecommunication charge information of each of the roaming areas in whichthe mobile communication terminal is located; and wherein thecommunication charge information notification means notifies the user ofthe communication charge information of each of the roaming areasacquired by the communication charge information acquisition means.
 8. Amobile communication system for allowing roaming communication of amobile communication terminal, the mobile communication systemcomprising: roaming area detection means for detecting whether or notthe mobile communication terminal is located in a roaming area based ona location registration request received from the mobile communicationterminal; communication charge information storage means for storingcommunication charge information indicating communication charges forthe roaming communication; communication charge information read meansfor reading the communication charge information of the roaming area inwhich the mobile communication terminal is located from thecommunication charge information storage means; communication chargeinformation transmission means for transmitting the communication chargeinformation read by the communication charge information read means tothe mobile communication terminal; and communication means forexchanging information relating to whether it is necessary for themobile communication system to transmit the communication chargeinformation to the mobile communication terminal between the mobilecommunication terminal and the mobile communication system; wherein thecommunication charge information includes version informationidentifying whether the communication charge information is the latestinformation based upon the version information; the communication chargeinformation transmission means having version information transmissionmeans in a part of the communication charge information transmissionmeans; and wherein the communication means exchanges informationrelating to whether it is necessary for the mobile communication systemto transmit the communication charge information between the mobilecommunication terminal and the mobile communication system based uponthe version information transmitted by the version informationtransmission means.
 9. A non-transitory computer readable mediumembodied with a computer program for execution by a mobile communicationterminal communicating with a mobile communication system, the programcomprising: a base station transmission information reception procedureof receiving information transmitted from a base station of the mobilecommunication system; a roaming area detection procedure of detectingwhether or not the mobile communication terminal is located in a roamingarea based on the information received by the base station transmissioninformation reception procedure; a communication charge informationacquisition procedure of acquiring communication charge information ofthe roaming area in which the mobile communication terminal is locatedwhen the roaming area detection procedure has detected that the mobilecommunication terminal is located in the roaming area; a communicationcharge information storage procedure of storing the communication chargeinformation of the roaming area acquired by the communication chargeinformation acquisition procedure; an update necessity inquiry procedureof inquiring of the mobile communication system whether it is necessaryto update the communication charge information stored in thecommunication charge information storage procedure; an updatedinformation reception procedure of receiving updated informationtransmitted from the mobile communication system when the mobilecommunication system has determined that it is necessary to update thecommunication charge information in response to the inquiry from theupdate necessity procedure; an update procedure of updating thecommunication charge information stored in the communication chargeinformation storage procedure based on the updated information receivedby the updated information reception procedure; a communication chargeinformation read procedure of reading the communication chargeinformation of the roaming area in which the mobile communicationterminal is located from the communication charge information storageprocedure based on information received by the base station transmissioninformation reception procedure when the roaming area detectionprocedure has detected that the mobile communication terminal is locatedin the roaming area; and a communication charge information notificationprocedure of notifying a user of the communication charge informationacquired by the communication charge information read procedure; whereinthe communication charge information includes version informationidentifying whether the communication charge information is the latestinformation, and the communication charge information storage procedurehaving a version information storage procedure in a part of thecommunication charge information storage procedure; the update necessityinquiry procedure having version information transmission procedure fortransmitting the version information stored in the version informationstorage procedure to a side of the mobile communication system, andfurther comprising: update-unnecessary information reception procedurefor receiving information that the communication charge information isnot a necessary update transmitted from the mobile communication systemwhen the mobile communication system has determined that thecommunication charge information stored in the communication chargeinformation storage procedure is the latest information in response tothe version information transmitted by the version informationtransmission procedure.
 10. The program according to claim 9, whereinthe communication charge information acquisition procedure includes acommunication charge information request procedure of requesting amobile communication system to provide the communication chargeinformation of the roaming area in which the mobile communicationterminal is located, and a communication charge information receptionprocedure of receiving the communication charge information transmittedfrom the mobile communication system in response to the request from thecommunication charge information request procedure.
 11. The programaccording to claim 9, further comprising: a roaming area notificationprocedure of notifying the user that the roaming area detectionprocedure has detected that the mobile communication terminal is locatedin the roaming area; wherein the communication charge informationnotification procedure notifies the user of the communication chargeinformation when directed by the user.
 12. The program according toclaim 9, wherein, when the user has issued a call instruction to adestination the user wishes to reach or a call preparation instructionto a destination the user wishes to reach in the roaming area in whichthe mobile communication terminal is located, the communication chargeinformation notification procedure notifies the user of thecommunication charge information for communication with the destinationthe user wishes to reach.
 13. The program according to claim 9, wherein,when receiving a call in the roaming area in which the mobilecommunication terminal is located, the communication charge informationnotification procedure notifies the user of the communication chargeinformation for communication after receiving the call when thereceiving call has been processed before the communication isestablished.
 14. The program according to claim 9, wherein, when theroaming area detection procedure has detected that the mobilecommunication terminal is located in two or more roaming areas, thecommunication charge information acquisition procedure acquires thecommunication charge information of each of the roaming areas in whichthe mobile communication terminal is located; and wherein thecommunication charge information notification procedure notifies theuser of the communication charge information of each of the roamingareas acquired by the communication charge information acquisitionprocedure.
 15. A communication charge notification method for executionby a mobile communication system for notifying a user of communicationcharge information for roaming communication of a mobile communicationterminal, the method comprising: an area detection step of detectingwhether or not the mobile communication terminal is located in a roamingarea based on information received by the mobile communication terminalfrom a base station; a communication charge information acquisition stepof acquiring communication charge information of the roaming area inwhich the mobile communication terminal is located when the areadetection step has detected that the mobile communication terminal islocated in the roaming area; and a communication charge informationnotification step of notifying the user of the communication chargeinformation acquired by the communication charge information acquisitionstep; wherein the communication charge information includes versioninformation identifying whether the communication charge information isthe latest information, and the communication charge informationacquisition step having a version information acquisition step, andfurther comprising: a communication step of exchanging informationrelating to whether it is necessary for the mobile communication systemto transmit the communication charge information between the mobilecommunication terminal and the mobile communication system based uponthe version information acquired in the version information acquisitionstep.